Ratings up for Fox News, CNN and HLN and down for MSNBC

Ratings for "The Rachel Maddow Show" on MSNBC show tumbled in the second quarter. (NBC)

Several high-profile news stories, including the Boston Marathon bombing, Edward Snowden's national security leaks, the conclusion of the Jodi Arias trial and the beginning of the George Zimmerman trial, lifted ratings at Fox News, CNN and HLN.

According to Nielsen, CNN saw its prime-time audience jump almost 50% for the quarter to an average of 666,000 viewers compared with the same period in 2012. In the 25-54 demographic, CNN was up 77%.

Fox News continued to dominate overall, finishing first in prime time with an average of 1.9 million viewers, a gain of 5%. However, the network was down 11% in adults 25-54.

HLN, which heavily covered the Jodi Arias murder trial, was up 49% in viewers in prime time to 518,000.

While Fox News, CNN and HLN all had something to crow about, MSNBC saw its ratings tumble. In prime time, its audience was down 16% to 576,000 viewers. Among adults 25-54, MSNBC's ratings fell 12%.

It was a particularly tough quarter for Rachel Maddow. Her show's average audience of 774,000 was the smallest since its debut in September 2008. A large part of the problem is "All In with Chris Hayes," which airs before Maddow's show and has yet to click with viewers.